llvm/test/Linker/Inputs/subprogram-linkonce-weak.ll
Adrian Prantl 4eeaa0da04 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266446 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-15 15:57:41 +00:00

17 lines
591 B
LLVM

define weak i32 @foo(i32 %a, i32 %b) !dbg !3 {
entry:
%sum = call i32 @fastadd(i32 %a, i32 %b), !dbg !DILocation(line: 52, scope: !3)
ret i32 %sum, !dbg !DILocation(line: 53, scope: !3)
}
declare i32 @fastadd(i32, i32)
!llvm.module.flags = !{!0}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!llvm.dbg.cu = !{!1}
!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, emissionKind: FullDebug)
!2 = !DIFile(filename: "foo.c", directory: "/path/to/dir")
!3 = distinct !DISubprogram(file: !2, scope: !2, line: 51, name: "foo", type: !4, unit: !1)
!4 = !DISubroutineType(types: !{})